Mimo based adaptive beamforming over ofdma architecture

ABSTRACT

A wireless communications system that combines Multiple Input/Multiple Output (MIMO), beamforming, and Orthogonal Frequency Division Multiple Access (OFDMA) techniques to facilitate increasing spectral efficiency of the communications system has been disclosed. A method of operating a wireless communications system includes transmitting first data in a first beam of electromagnetic signals generated by a first antenna array. The first data is associated with a first user. The first data is transmitted using a first OFDMA resource block of a radio frame. The method includes transmitting second data in a second beam of electromagnetic signals generated by the first antenna array. The second data is associated with a second user. The second data is transmitted using a second OFDMA resource block of the radio frame.

BACKGROUND

1. Field of the Disclosure

The present disclosure relates to communications technology and moreparticularly to wireless communications services using digitalmodulation techniques.

2. Description of the Related Art

A typical wireless communications network uses digital modulationtechniques (e.g., Quadrature Amplitude Modulation (QAM)) to increase thespectral efficiency (bps/Hz) of wireless communications. To increase theamount of data being communicated via QAM, the number of distinctamplitude levels used by the communication may be increased. However, toreduce or avoid degrading the communication reliability, an increase inthe number of distinct amplitude levels must be accompanied bysufficient channel capacity, which may be quantified by aSignal-to-Interference-plus-Noise-Ratio (SINR) for a particularcommunications distance. In addition, the increase in the number ofdistinct amplitude levels increases the required transmit signal power.However, in a typical wireless communications system, the transmitsignal power is limited by regulation. Thus, any increases in the numberof distinct amplitude levels must be accompanied by shortercommunications distances to maintain communications with an increasedSINR. A reduction in radio communications distance may result inincreased network costs due to an increase in the number of basestations and a decrease in cell size. Accordingly, improved techniquesfor increasing the spectral efficiency of a wireless communicationssystem are desired.

SUMMARY OF EMBODIMENTS OF THE DISCLOSURE

In at least one embodiment of the disclosure, a method of operating awireless communications system includes transmitting first data in afirst beam of electromagnetic signals generated by a first antennaarray. The first data is associated with a first user. The first data istransmitted using a first Orthogonal Frequency Division Multiple Access(OFDMA) resource block of a radio frame. The method includestransmitting second data in a second beam of electromagnetic signalsgenerated by the first antenna array. The second data is associated witha second user. The second data is transmitted using a second OFDMAresource block of the radio frame. The method may include scheduling thefirst user to the first OFDMA resource block and the second user to thesecond OFDMA resource block based on a firstSignal-to-Interference-plus-Noise-Ratio (SINR) indicator received fromthe first user and a second SINR indicator received from the seconduser. The method may include selecting a first modulation type of thefirst data and a second modulation type of the second data based on afirst SINR indicator received from the first user and a second SINRindicator received from the second user. The method may includegenerating first beamforming weights for the first beam and secondbeamforming weights for the second beam based on a first SINR indicatorreceived from the first user and a second SINR indicator received fromthe second user. The first OFDMA resource block may be the same as thesecond OFDMA resource block. The first and second beams may betransmitted during the same time slot of the radio frame. The first beammay be focused on a first receiver and the second beam may be focused ona second receiver.

In at least one embodiment of the disclosure, an apparatus includes aprecoder configured to generate a first signal based on firstbeamforming weights and first data associated with a first user. Theprecoder is configured to generate a second signal based on secondbeamforming weights and second data associated with a second user. Theapparatus includes a resource mapper configured to map the first signalto a first orthogonal frequency division multiple access (OFDMA)resource block of a radio frame. The resource mapper is configured tomap the second signal to a second OFDMA resource block of the radioframe. The apparatus includes a transmitter configured to transmit thefirst signal in a first beam of electromagnetic signals using a firstantenna array. The transmitter is configured to transmit the secondsignal in a second beam of electromagnetic signals using the firstantenna array. The apparatus may include a processor configured toschedule the first user to the first OFDMA resource block and the seconduser to the second OFDMA resource block based on a first SINR indicatorreceived from the first user and a second SINR indicator received fromthe second user. The apparatus may include a processor configured toselect a first modulation type of the first data and a second modulationtype of the second data based on a first SINR indicator received fromthe first user and a second SINR indicator received from the seconduser. The apparatus may include a processor configured to generate firstbeamforming weights for the first beam and second beamforming weightsfor the second beam based on a first SINR indicator received from thefirst user and a second SINR indicator received from the second user.The apparatus may include a plurality of antennas configured forMultiple Input/Multiple Output (MIMO) operation. The plurality ofantennas may include the first antenna array and a second antenna array.Individual antennas of the first antenna array may be configured to formthe first and second beams in a first frequency band. Individualantennas of the second antenna array may be configured to formadditional beams of electromagnetic signals in a second frequency banddifferent from the first frequency band.

In at least one embodiment of the disclosure, a method of operating awireless communications system includes receiving first data associatedwith a first user using a first orthogonal frequency division multipleaccess (OFDMA) resource block of a radio frame in a first beam ofelectromagnetic signals of a plurality of beams of electromagneticsignals in a service area of the first user. The plurality of beamsincludes a second beam of electromagnetic signals including second datain a second OFDMA resource block of the radio frame. The method mayinclude transmitting a first Signal-to-interference-plus-Noise-Ratio(SINR) indicator. The first resource block and a modulation type of thefirst data may be selected based on the SINR indictor. The first beam ofelectromagnetic signals may be formed based on the SINR indicator.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure may be better understood, and its numerousobjects, features, and advantages made apparent to those skilled in theart by referencing the accompanying drawings.

FIG. 1 illustrates an exemplary wireless communications network.

FIG. 2 illustrates an exemplary spectrum configuration for wirelesscommunications.

FIG. 3 illustrates an exemplary time division multiple accessconfiguration for wireless communications.

FIG. 4 illustrates an exemplary time division multiple accessconfiguration for wireless communications.

FIG. 5 illustrates frequency and time resource allocation for aMIMO-based adaptive beamforming orthogonal frequency division multipleaccess (OFDMA) communications consistent with at least one embodiment ofthe disclosure.

FIG. 6 illustrates an exemplary spectrum configuration for exemplaryMIMO-based adaptive beamforming OFDMA configurations for wirelesscommunications consistent with at least one embodiment of thedisclosure.

FIG. 7 illustrates an exemplary MIMO-based adaptive beamforming OFDMAconfiguration for wireless communications consistent with at least oneembodiment of the disclosure.

FIG. 8 illustrates an exemplary MIMO-based adaptive beamforming OFDMAconfiguration for wireless communications consistent with at least oneembodiment of the disclosure.

FIG. 9 illustrates a functional block diagram of an exemplary basestation for exemplary MIMO-based adaptive beamforming OFDMAcommunications consistent with at least one embodiment of thedisclosure.

FIG. 10 illustrates a functional block diagram of an exemplary physicalinterface of an exemplary base station transmitter consistent with atleast one embodiment of the disclosure.

FIG. 11 illustrates a functional block diagram of an exemplary physicalinterface of user equipment receiver consistent with at least oneembodiment of the disclosure.

The use of the same reference symbols in different drawings indicatessimilar or identical items.

DETAILED DESCRIPTION

A technique for improving the spectral efficiency of a wirelesscommunications network is disclosed. The technique combines MultipleInput/Multiple Output (MIMO) and beamforming techniques to facilitateincreasing the number of distinct amplitude levels used by a digitalmodulation technique (e.g., by Quadrature Amplitude Modulation (QAM)).In general, MIMO techniques use multiple radio transmitters and multipleelements in an antenna array to improve performance of wirelesscommunications. The beamforming technique may increase distance ofcommunication or increase the number of distinct amplitude levels usedby the digital modulation technique. MIMO uses space-divisionmultiplexing with spatially separated transmit and receive antennaelements. In general, increasing the number of diverse antenna elementsused and increasing the number of amplitude levels used for QAM toincrease the spectral efficiency requires an increase in SINR, whichresults in shorter distance coverage for a given total signal power.

In addition, in a typical MIMO system, all antenna elements transmitelectromagnetic signal power over an entire service area (e.g., cell orsector), which wastes a substantial amount of the transmitted power.That wasted power may be electromagnetic interference to neighboringreceivers and also may raise the noise level in the electromagneticenvironment. As a result, increasing the number of antenna elements inMIMO operation and increasing the number of amplitude levels of adigital modulation scheme increases spectral efficiency (e.g., measuredin bits per second per Hertz (bps/Hz (spectral efficiency) at theexpense of a reduced service area, thus reducing or eliminating anybenefit obtained from increasing the MIMO operation by increasing thenumber of amplitude levels of the digital modulation technique.

In general, beamforming technology improves the performance of thewireless communications network differently than MIMO. Beamformingalters the phase of each element in an antenna array to create spatialbeam patterns through constructive and destructive interference.Beamforming focuses the power of the transmitted electromagnetic wavesinto a narrower beam in the direction of the receiver instead oftransmitting in all directions (i.e., 360 degrees). Since theelectromagnetic waves are focused on the receiver, beamformingtransmission increases the system SINR, thus allowing the system tosupport increased numbers of distinct amplitude levels of the digitalQAM modulation without sacrificing the communication range. Adaptivebeamforming, which tracks users within the cell, is an effective way tosupport wireless communications.

In at least one embodiment of communications system, orthogonal coding,is combined with MIMO-based adaptive beamforming implementation using anOFDMA technique to increase spectral efficiency without reducing rangeof service for a particular transmit power and SINR. In contrast to atypical multi-user MIMO (MU-MIMO) system, adaptive beamforming is usedto serve a plurality of user sessions associated with corresponding userequipment receiving directions over a set of dynamically combinedresource blocks of the transmitted signal. The technique increases thespectral efficiency using spatial diversity of beamforming incombination with orthogonal coding, while increasing user access viaOFDMA. The technique supports multi-user access and increases spectralefficiency without loss of coverage area. In addition, the techniquereduces electromagnetic interference to neighboring cells.

Referring to FIG. 1, wireless communications network 100 includes anevolved packet core network including mobility management entity 112,serving gateway 114, packet data network gateway 116, and policy andcharging rules function (PCRF) 118. Mobility management entity 112performs signaling and control functions to manage access to networkconnections by user equipment 106 and user equipment 108, assignment ofresources to user equipment 106 and user equipment 108, and mobilitymanagement functions, e.g., idle mode location tracking, paging,roaming, and handovers. Mobility management entity 112 controls controlplane functions related to subscriber and session management for serviceto user equipment 106 and user equipment 108. In addition, mobilitymanagement entity 112 provides security operations including providingtemporary identities for user equipment, interacting with homesubscriber server 120 for authentication, and negotiation of cipheringand integrity protection algorithms. User equipment 106 and userequipment 108 each may be any wireless device directly used by anend-uses to communicate (e.g., hand-held telephone, smartphone, laptopcomputer, tablet, wearable device, or other device configured withwireless communications equipment including a wireless transmitter and awireless receiver). As referred to herein, a session is an activecommunication of data over a network between two devices and may includea first data stream from a first device to the second device and asecond data stream from the second device to the first device. It may bepossible to have more than one session between two devicessimultaneously.

Mobility management entity 112 selects suitable serving and Packet DataNetwork (PDN) gateways, and selects legacy gateways for handover toother networks. Mobility management entity 112 may manage a plurality(e.g., thousands) of base stations (e.g., enhanced Node-B (eNode-B)elements) or evolved packet data gateway elements. Serving gateway 114manages user plane mobility. Serving gateway 114 routes and forwardsuser data packets. Serving gateway 114 also behaves as a mobility anchorduring inter-eNode-B handovers and as the anchor for mobility betweenLong Term Evolution (LTE) and other 3GPP wireless technologies. Packetdata network gateway 116 provides connectivity from user equipment 106and user equipment 108 to external packet data networks by being thepoint of exit and entry of traffic for the user equipment. Policy andcharging rules function 118 interfaces with packet data network gateway116 and supports service data flow detection, policy enforcement, andflow-based charging. Home subscriber server 120 is a central databasethat stores user-related and subscription-related information. Homesubscriber server 120 provides mobility management, call and sessionestablishment support, user authentication, and access authorization.

Referring to FIGS. 1 and 2, in an exemplary implementation of wirelesscommunications system 100, base station 109 (which may include e.g., aLong Term Evolution eNode-B) assigns different resource blocks todifferent users. For example, resource block A is allocated to userequipment 106 and resource block B is allocated to user equipment 108.Those electromagnetic signals are not focused on the dedicated receiver(e.g., the electromagnetic signals are transmitted in all directions,e.g., power 405 of FIG. 2, and only power 407 and power 409 are receivedat user equipment) resulting in wasted power 403.

Referring to FIGS. 3 and 4, MIMO is implemented in a Multi-User-MIMO(MU-MIMO) system by implementing time division multiple access of allresource blocks of an OFDM system. However, that configuration ofcommunications system 100 can support only one user at a time. Forexample, during timeslot₁, user equipment 106 does not receive service.All resource blocks of the OFDM system are dedicated to providingservice to user equipment 108 and all of the transmit power is dedicatedto providing electromagnetic signals that includes those OFDM resourceblocks to user equipment 108. During timeslot₂, user equipment 108 doesnot receive service. All resource blocks of the OFDM system arededicated to providing service to user equipment 106 and all of thetransmit power is dedicated to providing electromagnetic signals thatinclude those OFDM resource blocks to user equipment 106.

Referring to FIG. 5, exemplary downlink OFDMA physical resourceallocation 600 includes resource grid 601. Radio frame 602, includesmultiple subframes 604 (e.g., two time slots). Each time slot 606includes N_(RB) ^(DL) downlink resource blocks, which may vary with aspecified bandwidth of a particular embodiment of a communicationssystem. The exemplary downlink OFDMA physical resource allocationincludes subcarriers in each resource block, and N_(symb) ^(DL) downlinkOFDM symbols in each resource block. The number of subcarriers variesbased on the width of each resource block (e.g., 180 kHz) and thesubcarrier spacing, Δf, of a particular embodiment of a communicationssystem (e.g., Δf=15 kHz, 15 kHz, or 7.5 kHz, N_(sc) ^(RB)=12, 12, or 24,respectively, and N_(symb) ^(RB)=7, 6, or 3, respectively, depending onwhether a normal or extended cyclic prefix is used). Each downlinkresource block 610 includes N_(sc) ^(RB)×N_(symb) ^(DL) resourceelements and the downlink resource grid includes N_(RB) ^(DL)×N_(sc)^(RB)×N_(symb) ^(DL) resource elements. Each resource element (e.g.,resource element 608) has an associated frequency subcarrier and asymbol index of a time slot of a radio frame. In at least one embodimentof the dynamic wireless OFDMA-based beamforming system, each antenna ofthe system has an associated resource grid 600 and the minimum radioresource that may be allocated is the minimum transmission time interval(TTI) in the time domain, which, in some embodiments of the dynamicwireless OFDMA-based beamforming system, is one subframe 604,corresponding to two resource blocks. Available downlink resource blocksmay be allocated to different users. The downlink resource blocks thatare allocated to a particular user are communicated by the eNode-B incontrol information to the user equipment over a control channel or byother suitable technique.

Referring to FIG. 6, in at least one embodiment of a wirelesscommunication system, multiple antenna elements of an antenna array areconfigured to transmit signals using a MIMO-based adaptive beamformingOFDMA technique. A plurality of elements of the antenna array areassociated with a particular frequency band of the electromagneticspectrum and are configured for communication with a first set of users.The same plurality of antenna elements of the antenna array areconfigured for communication with a second set of users in a differentfrequency band. For example, a first set of antenna elements of a phasedantenna array is configured for adaptive beamforming communication withuser equipment 702 and user equipment 704 using first portion of theelectromagnetic spectrum 714, e.g., first OFDMA resource blocks offrequency band 710. A second set of antenna elements of the phasedantenna array is also configured for adaptive beamforming communicationwith user equipment 706 and 708 using a second portion ofelectromagnetic spectrum 714, e.g., second OFDMA. resource blocks offrequency band 712. In at least one embodiment of the wirelesscommunications system, the second set of antenna elements of the antennaarray may be used for MIMO without adaptive beamforming.

Referring to FIGS. 7 and 8, antenna elements from the same array may beconfigured for adaptive beamforming to communicate with correspondinguser equipment using the associated OFDMA resource blocks. Referring toFIG. 7, in at least one embodiment of the wireless communicationssystem, eNode-B 716 communicates data to each user via a distinctfocused beam of unique resource blocks. For example, user equipment 702receives first user data from eNode-B 716 using beam 703 focused on userequipment 702. Beam 703 includes first OFDMA resource blocks offrequency band 710. User equipment 704 receives second user data fromeNode-B 716 using beam 705 focused on user equipment 704. Beam 705includes second OFDMA resource blocks of frequency band 710.

However, since beams 703 and 705 are being focused on separate userequipment in separate locations, beams 703 and 705 may not substantiallyinterfere with one another at the receivers of user equipment 702 and704 and unique resource blocks may not be required for transmission ofcorresponding data. Accordingly, in at least one embodiment of awireless communications system, resource blocks do not need to be uniqueto communicate with spatially diverse user equipment, i.e., userequipment in locations out of range of a beam focused on other userequipment. A scheduler may assign the same resource blocks in differentbeams to different user equipment. Referring to FIG. 8, in at least oneembodiment of the wireless communications system, eNode-B 716communicates data to each user equipment via a distinct focused beam,but reuses resource blocks. For example, user equipment 702 receivesfirst user data from eNode-B 716 using beam 707 focused on userequipment 702. Beam 707 includes first user data in first OFDMA resourceblocks of frequency band 710. User equipment 704 receives second userdata from eNode-B 716 using beam 709 focused on user equipment 704. Beam709 includes second user data in the first OFDMA resource blocks offrequency band 710.

Referring to FIG. 9, an exemplary base station (e.g., eNode-B 716)includes Radio Resource Control module 1010, Packet Data ConvergenceProtocol module 1008, Radio Link Control module 1006, Medium AccessControl module (MAC) and scheduler 1004, which includes a base stationscheduler that dynamically allocates and deallocates resource blocks toparticular users in a cell, and PHYsical layer module (PRY) 1002. MACand scheduler 1004 organizes data into transport blocks and schedulesdata for transmission to PHY 1002, which then formats the transportblocks into signals for transmission over the air. In at least oneembodiment, MAC and scheduler 1004 includes beamformer 1012, whichgenerates beamforming weights that are supplied to the PHYsical layermodule 1002 for combination with data for transmission using multipleantennas.

The base station uses multiple antenna arrays to transmit the samesignal appropriately weighted for each antenna element such that theeffect is to focus the transmitted beam in the direction of the targetreceiver of the user equipment and away from interference, therebyimproving the received signal-to-interference ratio. The user equipmentis not aware of the total number of physical antenna elements being usedby eNode-B 716 for the adaptive beamforming. The base station, usingbeamforming weights, combines into a single transmission, the signalsgenerated by multiple physical antenna elements. In at least oneembodiment of adaptive beamformer 1012, beamforming weights are selectedto result in beam patterns that may be dynamically adjusted to attenuateundesired signals while amplifying desired signals. At the userequipment, incoming signals to the receiver typically consist of desiredenergy and interference energy from other users or multipathreflection). An exemplary receiver characterizes each received signal interms of the direction of arrival (DOA) or angle of arrival (AOA). Theuser equipment may communicate related information to eNode-B 716 foruse by adaptive beamformer 1012. For example, user equipmentcommunicates a channel quality indicator to eNode-B 716. The channelquality indicator may contain information indicating a suitable downlinktransmission data rate, e.g., a modulation and coding scheme value basedon SINR at the user equipment, or other suitable information.

Adaptive beamformer 1012 may estimate the direction and distance of thetarget mobile receiver using any suitable signal processing techniques(e.g., Multiple Signal Classification (MUSIC) beamforming technique,Estimation of Signal Parameters via Rotational Invariance Techniques(ESPRIT), or Maximum Likelihood (ML) beamforming technique). Thebeamformer may extract a weighting vector for the antenna elements fromthese acquired directions of of the target mobile receiver, and uses itto transmit or receive the desired signal of a specific user whilesuppressing undesired interference signals. Any suitable algorithm fordetermining beamforming weights may be used.

Referring to FIG. 10, an exemplary PHY 1002 of FIG. 9, includes atransmitter path including channel coding processor 1120, scrambler(s)1102, modulation mappers 1104, layer mappers 1106, precoder 1108,resource mappers 1110, and OFDMA signal generators 1112, which generateradio frequency signals for transmission by one or more of antennas1130, 1132, . . . , 1140. For each codeword q provided by scrambler1102, modulation mapper 1104 modulates a block of scrambled bits {tildeover (b)}^((q))(0), . . . , {tilde over (b)}^((q))(M_(b) ^((q))−1) intoa block of complex-valued modulation symbols d^((q))(0), d^((q))(M_(s)^((q))−1), where M_(s) ^((q))is a number of modulation symbols in eachcodeword and depends on the modulation scheme. The relation betweenM_(s) ^((q)) and M_(b) ^((q)) is as follows:

${M_{s}^{(q)} = \frac{M_{b}^{(q)}}{Q_{m}}},$

where Q_(m) is the number of bits in the modulation constellation, withQ_(m)=2 for QPSK, Q_(m)=4 for 16 QAM, and Q_(m)=6 for 64 QAM. Othersuitable modulation schemes may be used. As Q_(m) increases, the numberof distinct amplitude levels increases. The particular modulation schemeimplemented is determined by the MAC layer according to the SINRachievable while not exceeding a predetermined transmitter power and notfalling below a predetermined SINR level, using the MIMO-based adaptivebeamforming OFDMA techniques described herein.

In at least one embodiment of the communications system, antennaelements 1130, 1132, . . . , 1140 are elements of a phased antennaarray, e.g., a group of multiple active antenna elements coupled to acommon source or load to produce a directive radiation pattern. Atypical active antenna element is an element whose energy output ismodified due to the presence of a source of energy in the element otherthan the mere signal energy which passes through the circuit or anelement in which the energy output from a source of energy is controlledby the signal input. Referring to FIGS. 6 and 10, in at least oneembodiment of a communications system, a subset of antenna elements1130, 1132, . . . , 1140 is used for communications over frequency band710 and another mutually exclusive subset of antenna elements 1130,1132, . . . , 1140 is used for communications over frequency band 712.Although six antenna elements are illustrated, any suitable number ofantennas may be used.

Referring back to FIGS. 7, 8, 9, and 10, adaptive beamformer 1012 of MACand scheduler 1004 determines beamforming weights, as described above.In addition, MAC and scheduler 1004 determines the modulation scheme,allocates resource blocks to individual users, and communicates themodulation scheme and allocation to modulation mapper 1104 and resourcemapper 1110, respectively, of PHY 1002. MAC and scheduler 1004 mayallocate resource blocks based on user throughput demands. Eachsubcarrier of the resource block may be assigned a modulation levelbased on the SNIR of the path between the antenna and the user. Ingeneral, increased modulation levels and increased numbers ofsubcarriers allocated to the user increase throughput to the user. In atleast one embodiment, MAC and scheduler 1004 allocates antenna elements1130, 1132, and 1134, to user equipment 702 and 704 and allocatesantenna elements 1136, 1138, and 1140 to user equipment 706 and 708. MACand scheduler 1004 may allocate user equipment 702 and user equipment704 the same OFDMA resource blocks or different OFDMA resource blocks.MAC and scheduler 1004 may allocate user equipment 706 and userequipment 708 the same OFDMA resource blocks or different OFDMA resourceblocks. MAC and scheduler 1004 may use beamforming weights that focusrespective beams on the corresponding user equipment. MAC and scheduler1004 determines the resource block allocation and selects a modulationscheme for each of the user equipment based on SINR information receivedfrom each of user equipment 702, 704, 706, and 708. In at least oneembodiment, MAC and scheduler 1004 selects the modulation scheme from apredetermined set of modulation schemes supported by the system,allocates OFDMA resource blocks, and determines associated beamformingweights that communicate the greatest number of bits over apredetermined communications distance with an SINR that does not fallbelow a predetermined SINR and a transmit power that does not exceed apredetermined transmit power for the eNode-B.

Precoder 1108 applies beamforming weights received from the MAC layer.The relative phases of the respective signals feeding the antennaelements are varied in such a way that the effective radiation patternof the array is reinforced in a desired direction and suppressed inundesired directions. In general, the spatial relationship of theindividual antennas also contributes to the directivity of the antennaarray. FIG. 11 illustrates exemplary user equipment receiver path forreceiving and recovering data from the electromagnetic signal receivedfrom eNode-B 716.

Thus, a wireless communications system that combines MIMO, adaptivebeamforming using OFDMA configurations to facilitate increasing spectralefficiency of the communications system has been disclosed. Structuresdescribed herein may be implemented using software executing on aprocessor (which includes firmware) or by a combination of software andhardware. Software, as described herein, may be encoded in at least onetangible computer readable medium. As referred to herein, a tangiblecomputer-readable medium includes at least a disk, tape, or othermagnetic, optical, or electronic storage medium.

The description of the disclosure set forth herein is illustrative, andis not intended to limit the scope of the disclosure as set forth in thefollowing claims. For example, while the disclosure has been describedin an embodiment in which a particular wireless network configurationand protocol is described, one of skill in the art will appreciate thatthe teachings herein can be utilized with other network configurationsand communications protocol having dynamically assignable resourceblocks. Variations and modifications of the embodiments disclosedherein, may be made based on the description set forth herein, withoutdeparting from the scope and spirit of the disclosure as set forth inthe following claims.

What is claimed is:
 1. A method of operating a wireless communicationssystem comprising: transmitting first data in a first beam ofelectromagnetic signals generated by a first antenna array, the firstdata being associated with a first user and the first data beingtransmitted using a first orthogonal frequency division multiple access(OFDMA) resource block of a radio frame; and transmitting second data ina second beam of electromagnetic signals generated by the first antennaarray, the second data being associated with a second user and thesecond data being transmitted using a second OFDMA resource block of theradio frame.
 2. The method, as recited in claim 1, further comprising:scheduling the first user to the first OFDMA resource block and thesecond user to the second OFDMA resource block based on a firstSignal-to-Interference-plus-Noise-Ratio (SINR) indicator received fromthe first user and a second SINR indicator received from the seconduser.
 3. The method, as recited in claim 1, further comprising:selecting a first modulation type of the first data and a secondmodulation type of the second data based on a firstSignal-to-Interference-plus-Noise-Ratio (SINR) indicator received fromthe first user and a second SINR indicator received from the seconduser.
 4. The method, as recited in claim 1, further comprising:generating first beamforming weights for the first beam and secondbeamforming weights for the second beam based on a firstSignal-to-Interference-plus-Noise-Ratio (SINR) indicator received fromthe first user and a second SINR indicator received from the seconduser.
 5. The method, as recited in claim 1, wherein the first OFDMAresource block is the same as the second OFDMA resource block.
 6. Themethod, as recited in claim 1, wherein the first and second beams aretransmitted during the same time slot of the radio frame.
 7. The method,as recited in claim 1, wherein the first beam is focused on a firstreceiver and the second beam is focused on a second receiver.
 8. Themethod, as recited in claim 1, further comprising: transmitting thirddata in a third beam of electromagnetic signals generated by a secondantenna array, the third data being associated with a third user and thethird data being transmitted using a third OFDMA resource block of theradio frame; and transmitting fourth data in a fourth beam ofelectromagnetic signals generated by the second antenna array, thefourth data being associated with a fourth user and the fourth databeing transmitted using a fourth OFDMA resource block of the radioframe.
 9. The method, as recited in claim 1, wherein each resource blockof the first plurality of OFDMA resource block includes a plurality ofresource elements, each resource element being defined by a frequencysubcarrier of a first frequency band and a symbol index of a time slotof the radio frame.
 10. The method, as recited in claim 1, furthercomprising: receiving, by the first user, the first data in the firstOFDMA resource block of the first beam; and receiving, by the seconduser, the second data in tire second OFDMA resource block of the secondbeam.
 11. An apparatus comprising: a precoder configured to generate afirst signal based on first beamforming weights and first dataassociated with a first user and configured to generate a second signalbased on second beamforming weights and second data associated with asecond user; and a resource mapper configured to map the first signal toa first orthogonal frequency division multiple access (OFDMA) resourceblock of a radio frame and configured to map the second signal to asecond OFDMA resource block of the radio frame; and a transmitterconfigured to transmit the first signal in a first beam ofelectromagnetic signals using a first antenna array and configured totransmit the second signal in a second beam of electromagnetic signalsusing the first antenna array.
 12. The apparatus, as recited in claim11, further comprising: a processor configured to schedule the firstuser to the first OFDMA resource block and the second user to the secondOFDMA resource block based on a firstSignal-to-interference-plus-Noise-Ratio (SINR) indicator received fromthe first user and a second SINR indicator received from the seconduser.
 13. The apparatus, as recited in claim 11, further comprising: aprocessor configured to select a first modulation type of the first dataand a second modulation type of the second data based on a firstSignal-to-Interference-plus-Noise-Ratio (SINR) indicator received fromthe first user and a second SINR indicator received from the seconduser.
 14. The apparatus, as recited in claim 11, further comprising: aprocessor configured to generate first beamforming weights for the firstbeam and second beamforming weights for the second beam based on a firstSignal-to-Interference-plus-Noise-Ratio (SINR) indicator received fromthe first user and a second SINR indicator received from the seconduser.
 15. The apparatus, as recited in claim 11, further comprising: aplurality of antennas configured for Multiple Input/Multiple Output(MIMO) operation, wherein the plurality of antennas comprises: the firstantenna array, individual antennas of the first antenna array configuredto form the first and second beams in a first frequency band; and asecond antenna array, individual antennas of the second antenna. arrayconfigured to form additional beams of electromagnetic signals in asecond frequency band different from the first frequency band.
 16. Theapparatus, as recited in claim 11, wherein the precoder is furtherconfigured to generate a third signal based on third beamforming weightsand third data associated with a third user, wherein the resource mapperis further configured to map the third signal to a third orthogonalfrequency division multiple access (OFDMA) resource block of the radioframe, and wherein the transmitter is further configured to transmit thethird signal in a third beam of electromagnetic signals using a secondantenna array.
 17. The apparatus, as recited in claim 11, wherein thefirst OFDMA resource block includes a plurality of resource elements,each resource element being defined by a frequency subcarrier and asymbol index of a time slot of the radio frame.
 18. The apparatus, asrecited in claim 11, further comprising: a first receiver associatedwith the first user, the first receiver being configured to receive thefirst data in the first OFDMA resource block of the first beam; and asecond receiver associated with the second user, the second receiverbeing configured to receive the second data in the second OFDMA resourceblock of the second beam.
 19. A method of operating a wirelesscommunications system comprising: receiving first data associated with afirst user using a first orthogonal frequency division multiple access(OFDMA) resource block of a radio frame in a first beam ofelectromagnetic signals of a plurality of beams of electromagneticsignals in a service area of the first user, the plurality of beamscomprising a second beam of electromagnetic signals including seconddata in a second OFDMA resource block of the radio frame.
 20. Themethod, as recited in claim 19, further comprising: transmitting a firstSignal-to-Interference-plus-Noise-Ratio (SINR) indicator, wherein thefirst resource block and a modulation type of the first data areselected based on the SINR indictor and the first beam ofelectromagnetic signals is formed based on the SINR indicator.